Fluorescence manipulation from graphene and hydrogen-terminated graphene covered Au nanoparticles

This paper presents the fluorescence manipulation of Rhodamine-6G (R6G) due to Au nanoparticles (Au-NPs) covered by pristine graphene and hydrogen-terminated graphene. By taking florescence signals of R6G on a quartz substrate as the standard reference, we observe an ∼fourfold increase in fluorescence intensity of R6G on bare Au-NPs deposited on the quartz substrate. However, this enhancement reduces to ∼1.8-fold when Au-NPs are covered by H-terminated graphene. In the case of Au-NPs covered by pristine graphene, the fluorescence of R6G is significantly quenched by a factor of ∼7.6-fold. The resulting fluorescence level can be attributed to the local field enhancement from Au-NPs and the quenching effect of graphene in the Au–graphene hybrid nanostructure, which are confirmed by our controlled experimental and simulation results. Our work reveals that the surface modification of metal NPs by graphene materials would bring a great impact on fluorescence, providing a simple approach for artificially manipulating fluorescence for specific molecular sensing, detecting, and imaging.